1. Field of the Invention
The present invention relates to a device which generates a desired motion trajectory of legs of a legged mobile robot such as a biped locomotion robot.
2. Description of the Related Art
A legged mobile robot (hereinafter, simply referred to as “robot” in some cases) moves by repeating a leaving motion and a landing motion of each leg. Therefore, when moving the legged mobile robot, it is necessary to determine a desired position (desired landing position) on a floor surface where each leg is landed on the floor by the landing motion of the leg subsequent to the leaving motion thereof and a desired motion trajectory which defines the movement in the air.
As a method of generating the desired motion trajectory of each leg in this manner, for example, as disclosed in Japanese Patent Application Laid-Open No. 2010-253655 (hereinafter, referred to as Patent Document 1), there is known a method of preparing a plurality of candidates for a desired motion trajectory of each leg, measuring the configuration of a floor ahead in the moving direction of the robot, and selecting and determining a desired motion trajectory able to avoid a bump on the measured floor out of the plurality of candidates.
In the case of operating the robot in various environments, however, the configuration of the floor surface where the robot is moved is widely various. Moreover, it is difficult to prepare a plurality of candidates for the desired motion trajectory of each leg so as to be adaptable to the wide variety of floor surfaces.
Therefore, the technique disclosed in Patent Document 1 described above easily causes a situation where it is impossible to find a desired motion trajectory able to appropriately move the robot from the prepared candidates for the desired motion trajectory, depending on the configuration of the floor surface in the environment where the robot is to be moved. Consequently, it is difficult to move the robot in various environments.
In addition, when determining the desired motion of each leg or the like of the robot, generally the conventional robot control technique determines the desired motion on the premise that the floor surface in the operating environment of the robot has a basically constant or uniform configuration over a relatively wide range.
In the various operating environments, however, the floor surface often does not have the constant or uniform configuration over a wide range.
Therefore, it has been desired a technique of determining a motion trajectory of a leg of the robot so that the robot is able to move even in the above situation.
The present invention has been provided in view of the above background. Therefore, it is an object of the present invention to provide a device which generates a motion trajectory of a leg of a legged mobile robot so that the legged mobile robot is able to move in various environments.